Angiogenesis Inducing Agents/biosynthesis; Breast Neoplasms/metabolism; Cell Hypoxia/physiology; Gene Expression Regulation, Neoplastic; Growth Substances/biosynthesis; Immediate-Early Proteins/biosynthesis; Intercellular Signaling Peptides and Proteins; Angiogenesis Inducing Agents/genetics; Angiogenesis Inducing Agents/pharmacology; Animals; Connective Tissue Growth Factor; Endothelial Growth Factors/genetics; Endothelial Growth Factors/metabolism; Endothelial Growth Factors/pharmacology; Endothelium, Vascular/drug effects; Endothelium, Vascular/physiology; Enzyme-Linked Immunosorbent Assay; Female; Fibroblast Growth Factor 2/pharmacology; Growth Substances/genetics; Growth Substances/pharmacology; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Immediate-Early Proteins/genetics; Immediate-Early Proteins/pharmacology; Lymphokines/genetics; Lymphokines/metabolism; Lymphokines/pharmacology; Mice; Neovascularization, Physiologic/drug effects; RNA, Messenger/genetics; RNA, Messenger/metabolism; Transcription Factors/genetics; Tumor Cells, Cultured; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors